1. Field of the Invention.
The present invention relates to a guidewire extension system including an extension guidewire having a connecting assembly at the distal end thereof for releasably and firmly connecting to a proximal end of an initially inserted PTCA guidewire having a dilatation balloon catheter positioned thereon and situated within a guiding catheter inserted into a femoral artery or carotid artery, for enabling the dilatation balloon catheter to be removed and replaced with another dilatation balloon catheter.
2. Description of the related art including information disclosed under 37 CFR .sctn..sctn. 1.97-1.99
Heretofore, it has been proposed to provide an exchange guidewire which, after removal of a shorter initially inserted guidewire, is inserted through a dilatation balloon catheter situated in a guiding catheter inserted femoral artery for the purpose of replacing the dilatation balloon catheter.
Since the procedure of utilizing an exchange guidewire is tedious, painstaking, time consuming and has some risk involved, it has also been proposed to utilize a guidewire extension for introducing a new dilatation catheter into a cardiovascular system.
For example, there is proposed in U.K. Patent Application No. 2 180 454 A guidewire system where the proximal end of an initially inserted guidewire is received in a sleeve which is also received over the distal end of an extension wire and the sleeve is crimped to fix the mating ends of the guidewire and extension wire together.
Also, an extendable guidewire system has been proposed in U.S. Pat. No. 4,827,941 wherein a small diameter proximal end portion of a primary or initial guidewire is frictionally received within a tubular member fixed to a distal end of a guidewire extension section.
Further, an extendable guidewire for introducing a dilatation catheter into a cardiovascular system has been proposed in U.S. Pat. No. 4,875,489 where the proximal end of a main guidewire has a tapered end portion which is received into a tubular member having a slit or slot therein which permits it to expand, the tubular member being received within an outer sleeve and fixed to a reduced in diameter distal end of a section of an auxiliary guidewire.
As will be described in greater detail hereinafter, the guidewire extension system of the present invention provides a simple connecting assembly including a coiled wire spring for quickly and firmly connecting (locking) the proximal end of an initially inserted guidewire to an extension guidewire and which permits quick and simple disengagement of the initially inserted guidewire from the connecting assembly.